The present invention relates to electronic countermeasures and more particularly to countermeasures against long-range radars which employ pulse-compression techniques. Long-range radars such as those which would be carried by a surveillance satellite employ pulse-compression systems to increase their average transmitted power without encountering arcing or breakdown in their waveguides and without sacrificing range resolution. Unlike terrestrial waveguides which can be pressured so as to be able to transmit increased power without arcing, spaceborne radars must necessarily operate in the vacuum of space. This poses limits on the power that can be transmitted, and hence there is a need for pulse-compression radar. These pulse-compression systems transmit a long-pulse frequency or phase coded to increase the bandwidth and compress returns to pulses whose lengths are inversely proportional to the transmitted pulse bandwidth. On compression the complete echo pulse must index into the compression decoder before the compressed pulse exits.
Since the space-borne radar in orbit is normally hundreds of miles away from the target and could be up to two thousand miles away, the power incident upon the target is very small. This fact gives rise to the suggestion of low-cost, low-power, expendible electronic countermeasures systems.